<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>大文件上传&合并</title>
     <base href="./">
    <script src="https://unpkg.com/axios@0.24.0/dist/axios.min.js"></script>
  </head>
  <body>
    <input id="fileInput" type="file" />
    <button id="button">合并文件</button>
    <script>
      const fileInput = document.querySelector('#fileInput');
      const button = document.querySelector('#button');

      const chunkSize = 20 * 1024; // 20KB
      let randomStr = '';
      let fileName = '';
      fileInput.onchange = async function () {
        const file = fileInput.files[0];
        randomStr = Math.random().toString().slice(2, 8);
        fileName = file.name;
        const chunks = [];
        let startPos = 0;
        while (startPos < file.size) {
          chunks.push(file.slice(startPos, startPos + chunkSize));
          startPos += chunkSize;
        }

        const tasks = [];
        chunks.map((chunk, index) => {
          const data = new FormData();

          data.set('name', randomStr + '_' + file.name + '-' + index);
          data.append('files', chunk);
          tasks.push(
            axios.post(
              'http://127.0.0.1:3333/api/large-file-upload/upload',
              data,
            ),
          );
        });
        await Promise.all(tasks);
      };

      button.onclick = async function () {
        axios.get(
          'http://127.0.0.1:3333/api/large-file-upload/merge?name=' +
            randomStr +
            '_' +
            fileName,
        );
      };
    </script>
  </body>
</html>
